This summer has seen some particularly debilitating heat waves in many parts of the country. Some places have seen temperatures in the 120’s and the Northeast has boiled in hot, steamy weather for days and even weeks on end.
With so much attention on global warming, it is sensible to ask whether climate change is a factor in this hot summer.
Recent studies have shown that 2005, 2007, 2010, and 2011 were warmer than any other year going back 600 years to the 15th century. 2013 has a long way to go, so it remains to be seen how this year will end up in the big picture.
But what about these recent heat waves? Meteorologists attribute them to something called a “blocking event”. These occur when a particular configuration of the jet stream pinches off a large air mass from the normal wind flow and it basically gets stuck in place. These blockages can last for several days or even weeks and cause weather patterns to stall over one area fueling floods, droughts, heat waves and other extreme weather events.
Are we seeing more of these blocking events because of global warming? Quite possibly. But it is probably not very safe to assume that any particular heat wave or other extreme weather event is directly attributable to climate change. Sometimes they just happen.
What we do know is that with rising mean temperatures, the variability of our weather is likely to increase and extreme events that were relatively rare may become increasingly common.
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Web Links
What’s Behind the Heat Wave: Climate Change or Weather?
Photo, taken on July 18, 2011, courtesy of NASA Goddard Space Flight Center via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.